Odd facts:
Tigers are the closest relative to lions.
Lions are the second largest of the big cats, after the tiger.
A lion's roar can be heard up to 5 miles (8 kilometers) away, according to the National Zoo.
A male lion's mane protects it when it fights.
At short distances, lions can run 50 mph (80 kph). They can jump as far as about 36 feet (11 m).
Asiatic lions have skimpier manes than their African cousins and have a characteristic skin fold on their belly, according to the WWF. An African lions' ears are always hidden by its mane, while an Asiatic lions ears are visible.
Female lions will copulate on average 3,000 times for each cub that survives for a year.